I'm running the 12/9/15 version of beta. A quick test using the MP4 Normal profile setting has it choosing Handbrake. It detects NVENC support with a PASS and then chooses Handbrake without hardware acceleration. Let me know if you want me to test anything
else. I'm currently installing the 12/11 release, but it doesn't look like anything changed that would affect hardware acceleration.

I swear I replied to this last week, but I don't see my reply now. Here is what I've found using the latest beta build. MCEB does correctly detect NVENC and now selects FFMPEG over Handbrake. That part seems to work great. I did notice that the test for
NVENC was run an additional time, which seems redundant.

What still doesn't seem to work, is setting the proper parameters for NVENC. MCEB is still passing to FFMPEG the x264 options (which don't work with NVENC). Since the default profiles do most of their settings in x264 options, the encode uses "default"
NVENC parameters for most things and this results in a lower quality than the profile would achieve using x264. I know that NVECN is never going to be comparable to x264, but letting all the parameters default definitely results in lower quality. This is the
FFMPEG video options I've decided on for me in a custom profile that give pretty good results:
ffmpeg-video=-vf yadif=0:-1:1,hqdn3d,scale=1280:720 -vcodec nvenc_h264 -b:v 3M -bufsize:v 6M -maxrate 5M -preset hq -bf 3 -refs 5 -b_strategy 2 -me_method umh -me_range 16 -sc_threshold 40 -subq 8 -trellis 1 -chromaoffset -2 -i_qfactor 1.40 -g 250 -keyint_min
25 -qcomp 0.60 -qmin 0 -qdiff 4 -r 30000/1001 -profile:v high -level 4.0

In my custom profile I've also set ffmpeg-VideoOptimized=true so MCEB doesn't mess with any of my settings or else it tries to scale my bitrate when going from 1080i to 720p (my desired output size).

I've uploaded my new log file to the FTP site with this name: Discussion 648531-FFMPEG_NVENC.log

This is my complete video options from my custom profile I'm testing. I'm getting really good quality with this. I pretty much just translated the options from the x264 "slow" profile into ffmpeg options, where I could, to come up with these options.